Science et changements planétaires / Sécheresse


Effet de serre et activités humaines (gaz à effet de serre d’origine anthropique) Volume 4, issue 4, Décembre 1993

GREF, Ministère de l’Agriculture et du Développement rural, 30, rue Las Cases, 75349 Paris 07 SP, France.
  • Page(s) : 211-20
  • Published in: 1993

The greenhouse effect is a naturel phenomenon occurring in the earth’s atmosphere due to the presence, in very small concentrations, of gases such as carbon dioxide, water vapour and methane. Because of this, the qround temperature is 33 °C higher than it would be due to solar radiation balance alone. For more than a century, however, human activity has contributed towards a marked increase in the levels of these gases and also added other particularly active ones like CFC. Climatic models and paleoclimatology predict - according to the economic scenario selected and hypotheses as to how the atmosphere and oceans function - that the increase in these levels will result in a mean warming of 1.5 to 4.5 °C and a rise of sea level of between 30 to 60 cm over the next hundred years. The consequences would be wide-reachinq, if not catastrophic, for mankind and the entire ecology of the planet. To minimise the risks, serious problems and multifarious drawbacks these climatic upheavals could cause, major changes in the use of fossil fuel - especially for transport -, as in forming and forestry practice, must be mode.